Electromagnetic pickup devices are used in conjunction with electric stringed musical instruments such as electric guitars and basses to convert the vibrations resulting from the movement or “picking” of the strings into electrical signals, for subsequent transmission to amplification devices to produce a desired sound. The pickup is generally positioned under the strings of the instrument on the base surface and the signal transmitted by an electromagnetic pickup is dependent upon the motions of each string.
Pickup devices are commonly fit into cavities within housings that are attached to the musical instrument body or directly into cavities within the body of the musical instrument. In the past, the depth of these cavities was determined by how much depth was needed to adjust particular components of the pickup up or down. For example, the pickup cavity in a Les Paul electric guitar is approximately ⅞th inch. However, conventional wisdom holds that the shallower the pickup cavity, the better the tone because of a reduction in the amount of material removed from the cavity.
The most essential components of a pickup are a permanent magnet and a coil of wire. There are several types of pickups with varying coil configurations known in the art. One type of electromagnetic pickup device is a single coil pickup. In a single coil pickup, a single coil portion has a plurality of magnetic pole pieces, with each pole piece associated with a string of the instrument. The pole pieces lie in a place spaced from the common plane of the strings, with each string disposed in a play extending through a space between two adjacent pole pieces, so that a given string at rest is located above and between two adjacent pole pieces. Another type of pickup is a dual coil pickup or a humbucking pickup. In a humbucking pickup, two coils are associated or connected in a manner so as to reduce hum. Dual Coil pickups may also have pole pieces.
There is significant value in a cavity design for a pickup which allows for the least amount of material to be removed from cavity while still allowing the pickup to work for its intended purpose. In many cases, it is also valuable for the cavity design to allow the pickup to be placed on the musical instrument body in an esthetically pleasing manner.